FORENSICS: BLOOD

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Transcript of FORENSICS: BLOOD

bloodWHATWHYHOW- Blood typing: provides class evidence

- Use white blood cells to obtain DNA evidence

- Recreate a crime scene with blood spatter evidenceor... recreate other thingsplasmared blood cellswhite blood cellsplateletsRED BLOOD CELLS:Also known as erythrocytesMain function is to carry oxygen and carbon dioxide This is accomplished through hemoglobin, an iron- containing protein**Red blood cells don't have nuclei.**So, red blood cells alone cannot be used toobtain DNA evidenceHemoglobin makes blood red when oxygenis bound to it.WHITE BLOOD CELLSAlso know as leukocytesWhite blood cells guard against infection, fight parasites, and attack bacteria.What does a high white blood cell count tell you?White blood cells do have nuclei, so you can obtain DNA evidence from them.PLATELETS:Cell fragments that come together to form blood clotsPLASMA:The fluid component of blood Mostly waterDissolved in the water are chemicals: salts, proteins, hormones, and waste, to name a fewBLOOD TYPING:Less expensive than DNA profilingCan be used to link or exclude a suspect to the crime sceneBLOOD TYPING:The surfaces of all blood cells contain certain proteinsProteins are either A proteins or B proteinsPeople have either an A, B, AB, or O blood typeTHE RH FACTOR:Another type of red blood cell surface protein: Rh factor85% of the population has this protein on their red blood cells (Rh+)This is where the "+" or "-" comes from in labeling a person's blood type.O- means...U,S. BLOOD TYPE PERCENTAGES:Type O - 43%Type A - 42 %Type B - 12 %Type AB - 3%WHAT'S UP WITH THOSE ANTIBODIES?